Quickly Test If It's Time to Buy a New Pillow
Pillows have a limited lifespan. If you can't remember the last time you replaced yours and want to quickly see if it's time for a new one, try this simple test.
Real Simple recommends:
Fold your pillow in half, squeezing out the air. If it doesn't spring back to shape, you're overdue for a new one. Otherwise, so long as they don't smell mildewy, you only need to replace your pillows every three to five years-any longer, and they begin to lose support.
Pillows are also one of those things
When to Buy a New Pillow | Real Simple
Photo by pmarkham.